Description
Alarm Valve is a double seated clapper check valve
with grooved seat design, which ensures positive
water flow for alarm operation and is designed for
installation in wet pipe sprinkler system. External
bypass prevents false alarm under all supply pressure
condition. In the event of variable pressure condition,
false alarm is prevented with the provision of retard
chamber, thus the design allows for installation under
both variable and constant supply pressure condition.
Operation of one or more automatic fire sprinklers
causes the water to flow into the sprinkler system
causing the alarm valve to open, allowing continuous
flow of water into the system and transmittal of
alarms, both electrical and mechanical.
OPERATION
The fire protection system initially when being
pressurized, will allow water to flow into the system
until water supply and system pressure is equalized
and the clapper closes the waterway. Once the
pressure is stabilized, the fire protection system
is ready to be placed in service and then the alarm
control valve must be opened. Under normal condition,
the water pressure gauge connected to the system
side of the alarm valve would show a higher or equal
pressure reading than the water pressure gauge
connected to the supply side of the valve. This occurs
because of the bypass line connecting downstream
and upstream side of the alarm valve, which allows
water pressure surge to pass without lifting the valve
clapper off its seat, thereby causing excessive high
pressure surge entrapped in the system side due to
presence of a check valve, which generally prevents
false alarm
